SILPHIUM LACINIATUM. COMPASS PLANT. 187 



and south, with the flat surfaces necessarily east and west. 

 When the leaves become heavy, or are blown about by the wind, 

 the north and south direction, though rarely wholly lost, is not so 

 apparent ; and this accounts for the doubts of those who have 

 not had the opportunity of watching the growth from its earlier 

 start in spring. In these latter cases the polarity is incontestable. 

 How long this curious fact has been known is not clear. Dr. C. 

 C. Parry, in the Botany of Owen's Geological Survey of Minne- 

 sota, published in 1S52, refers to it as the " Compass " plant; 

 but whether because this was the name in general use, or be- 

 cause the peculiarities of the plant had been brought to the 

 attention of science a few years before, does not appear. The 

 poet Longfellow, in "Evangeline," issued in 1847, referred to the 

 popular notion, and General Alvord seems to have been the first 

 to attract scientific attention to the plant in 1848. Longfellow's 

 lines are well known. Evangeline is almost in despair at the 

 long absence of her lover, and — 



" ' Patience ! ' the priest would say ; " have faith, and thy prayer will be answered ; 

 Look at this delicate plant that lifts its head from the meadow ; 

 See how its leaves are turned to the north, as true as the magnet — 

 This is the compass-flower, that the finger of God has planted 

 Llere in the houseless wild, to direct the traveller's journey 

 Over the sea-like, pathless, limitless waste of the desert. 

 Such in the soul of man is faith. The blossoms of passion, 

 Gay and luxuriant flowers, are brighter and fuller of fragrance ; 

 But they beguile us and lead us astray, and their odor is deadly. 

 Only this humble plant can guide us here, and hereafter 

 Crown us with asphodel flowers, that are wet with the dews of nepenthe.' " 



The reason for this turning of the edge of the leaves to the 

 north and the south has not been satisfactorily determined. Dr. 

 Engelmann, in a paper read before the " American Association 

 for the Advancement of Science," at St. Louis, in 1878, noted 

 that the leaves had stomata on both sides. Plants in general 

 have stomata only on the under surface, and this is taken to 

 mean that stomata do not like light. Prom this Dr. Engelmann 

 suggested that as the compass plant has these on both sides, 

 there was an evenly balanced struggle to avoid the liL^ht, which 



